The overall objective of this project is to determine why high blood levels continue to occur in bridge construction workers despite government regulations and industry recommendations. Specific aims are: (1) Measure lead particle exposure in three particle size fractions and perform surface wipe measurements for 150 Massachusetts bridge construction workers at thirty (fifteen per year for two years) State Highway Department sites; three to five exposure measurements will be taken during a two-week study period at each site. (2) Perform a set of structured observations of work practices and the use of personal protective devices and control technologies coinciding with exposure measures. These observations will be combined into ordinal index variables representing various aspects of worker protection. (3) Perform a project baseline blood lead on this group, followed by a second measurement 14 days later. These will be compared for each worker and as a group, and if possible associated with activities in the period. (4) Use ethnographic techniques to assess worker and management awareness of lead poisoning issues. (5) Develop predictors of blood lead and air concentrations using industrial hygiene controls, work practice, training and company and worker attitude variables. Workers will be interviewed with a questionnaire based on one from a previous study, and will be asked to keep a work task diary for two weeks. Blood samples and air samples will be taken to determine individual exposures, and other information on environmental conditions will be collected.A personal exposure score will be developed and used in the analysis. The analysis of data collected over the two year period will be focused on associations between specific work activities and environmental factors and blood and airborne lead levels for bridge repair and maintenance workers. The basic methods of analysis will be analysis of variance and analysis of covariance.